Promotional price for official launch, offer valid Sept 25, 2025- Oct 25, 2025
What is L2 Dual-Combo Set?
L2 Dual-Combo Set includes two premium filters: one L-eXtreme and one L-Synergy.
L-eXtreme:The L-eXtreme is a dual-narrowband filter (OIII-7nm & Ha-7nm) designed to exclusively transmit the key nebula emission lines of OIII (500.7nm) and Hα (656.3nm). By effectively blocking all other light pollution emission lines, it ensures that only the signals from OIII and Hα elements are captured during imaging, achieving maximum effective transmission. With years of technological refinement, it significantly optimizes the performance in suppressing bright star halos.
L-Synergy：The L-Synergy is a dual-narrowband filter (OIII-7nm & SII-7nm) that guarantees high transmission for both the SII (672.4nm) and OIII (500.7nm) spectral lines, while offering exceptional out-of-band rejection for all other wavelengths. By effectively blocking all other light pollution emission lines, it ensures that only the signals from OIII and SII elements are captured during imaging, achieving maximum effective transmission. With years of technological refinement, it significantly optimizes the performance in suppressing bright star halos.
Why is L2 Dual-Combo Set? (Advantages)
The L2 Dual-Combo Set is engineered to unleash the power of Hubble Palette imaging for color camera users, supporting telescope systems as fast as F3.3, and above ( slower system).
Tailored specifically for color camera astrophotographers, this set includes two premium filters: OIII & Hα (L-eXtreme),OIII & SII (L-Synergy).
This innovative combination breaks through the traditional limitations of narrowband imaging with color cameras. Without the need to switch to a monochrome camera or invest in an expensive SHO three-filter set, users can achieve stunning Hubble Palette images at a fraction of the cost and complexity.
The core appeal of this combination design lies in lowering barriers and expanding possibilities for colour camera users: it preserves the equipment advantages of colour cameras while enabling users to unlock “Hubble-like” creative capabilities at minimal cost through minimalist filter combination. Simultaneously, it offers greater flexibility for astrophotography.
Whether capturing nebular detail or reproducing deep-sky colours, this combination enables richer creative expression, truly unlocking the full potential of colour cameras in deep-sky photography.
Optical Design
Based on the characteristics of celestial emission lines and light pollution emission lines, the L2 Dual-Combo Set preserves the distinctive colours of nebulae in OIII, Hα, and SII while filtering out the vast majority of light pollution. Specifically designed and optically optimized, its transmission profile is as follows:
*We will continue to optimize the product based on test results. This curve does not represent final product specifications.
How to read the chart?
▲The horizontal axis is the Wavelength in Nanometers(nm).
▲The vertical axis is transmission in %.
Coating Technology
- Multi-layers anti-reflection coating
- Non-cementing optical substrate coating
- Optolong filter adopts precision coating based on Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL(central wavelength) no deviation affected by temperature change.
- Planetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band.
| Specification | |
| 2" (M48×0.75) |
L2 Dual-Combo Set Packing Style
Outer Box: Gift set packing
Plastic Box: PP material
Lining: imported high pressure BLACK EVA material
L2 Dual-Combo Set Performance
I. NGC 7000 in SHO©RONALD BRECHER
NGC 7000 (also called the North America Nebula) dominates the left side of this image, and NGC 5070 (the Pelican Nebula) is to the right. These clouds of gas are part of a huge complex of emission nebulae lying about 1,600 light years away in northern Cygnus. With an apparent magnitude (brightness) of 4, in theory this object is visible to the naked eye, even though its light is very spread out. I have seen it with my naked eye and with low power binoculars in dark skies north of where I live. It looks like a faintly hazy, irregular patch of grey.
I have previously imaged this region in a wide field and at higher resolution. For example, you can find images of the Cygnus Wall (the “Central America” region) and the Pelican.
All but one of my prior images has been in natural broadband colour, dominated by red emissions of hydrogen. For this image I used two Optolong dual-narrowband filters designed for colour cameras. The Optolong L-eXtreme passes hydrogen and oxygen emissions; the brand-new L-Synergy filter passes sulphur and oxygen emissions. I combined the data from the two filters assigning sulphur to red, hydrogen to green, and oxygen to blue, making the traditional Hubble Palette. As you can see from the image, the filters worked great. It will be available for purchase soon. This is the first narrowband image made with the 70mm f/7 Sky-Watcher Esprit EDX refractor. Sky-Watcher hopes to have them available to buy by the end of 2025. Here is some preliminary information about the new Esprit EDX line.
Tekkies:
Acquisition, focusing, and control of Paramount MX mount and other equipment with N.I.N.A. and TheSkyX. Unguided. Focus with Primalucelab Sesto Senso 2 on the Sky-Watcher stock focuser. Equipment control with Primalucelab Eagle 4 Pro computer. All pre-processing and processing in PixInsight. Acquired from my SkyShed in Guelph. Acquired under average transparency and seeing and moderate to strong moonlight from August 31 – September 8, 2025.
Sky-Watcher Esprit 70 EDX refractor, QHY367C Pro camera.
L-Synergy Filter: 147 x 5m = 11hr 50m
L-eXtreme Filter: 140 x 5m = 11hr 40m
Total: 23hr 30m
Data Reduction and Linear Processing
Preprocessing: The WeightedBatchPreProcessing script was used to perform calibration, cosmetic correction, weighting, registration, local normalization, integration and Drizzle integration of all frames (Fast Drizzle, Scale=2x, Drop Shrink=0.9).
Gradient Removal: DynamicBackgroundExtraction was applied to the two masters (L-Synergy = SOO; L-eXtreme = HOO).
SHO Master Creation: PixelMath was used to create an SHO using the equations:
R=SOO[0]
G=HOO[0]
B=0.25 x (SOO[1] + SOO[2]+HOO[1] + HOO[2]
Deconvolution: BlurXterminator was applied to the SHO image using an automatic PSF, star sharpening set to 0.10, and “Correct First” selected.
By Ron Brecher
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